Equity Investments (Details 6) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Expenses
Real estate taxes	$ 4,765	$ 4,427	$ 2,412
Real Estate Investment [Member]
Summarized statements of operations of real estate equity investments
Total revenue	89,595	54,600	49,071
Expenses
Operating	31,053	22,340	20,342
Real estate taxes	7,274	5,978	5,873
Interest	22,101	13,330	9,033
Depreciation and amortization	21,724	16,068	13,616
Other expenses	5,895	929	486
Total expenses	88,047	58,645	49,350
Other income
Gain from extinguishment of debt			2,207
Net income (loss)	1,548	(4,045)	1,928
Trust's share of net income (loss)	$ 5,606	$ (1,635)	$ 1,109